Polyolefins are a class of polymers derived from simple olefins. Most commonly, methods of making polyolefins involve the use of Ziegler-Natta polymerization catalysts. These Ziegler-Natta polymerization catalysts polymerize vinyl monomers using a transition metal halide to provide a polymer with an isotactic stereochemical configuration.
A type of Ziegler-Natta catalyst system that is traditionally used for the polymerization or copolymerization of olefins comprises TiCl3 based catalysts components obtained, for example, by the reduction of TiCl4 with Al-alkyls, used in combination with Al-compounds such as diethylaluminum chloride (DEAC). These catalysts are characterized by a very low activity which results in the presence of large amounts of catalytic residues in the polymers.
During the past 30 years, numerous Ziegler-Natta catalysts have been developed which can afford improved activity in olefin polymerization reactions.
However, there still remains a need for development of new internal electron donor compounds that can provide highly desirable activity in olefin polymerization reactions and increased contents of crystalline isotactic fractions in the olefinic polymers they produce.